I've done GUI app development (in an educational context only) in Java via Swing, VB, VC++, and VC#. Of all of the methods for layout, Swing freaked me out having such a different way of handling controls. I'm so used to the idea of fixed pixel points that having something like that kinda overwhelms me. The .Nyet interface has some limited Swing-like mapping options, but not many that I've seen so far.
Probably should give some of those others a shot one of these days.